A date with Lucy (and Ida, too)

Against all hope I brought my camera along with me. Special exhibitions do not usually let you take photos, and soon after I arrived at the Discovery Times Square Exhibition with Amanda and her boyfriend J I was forced to hand over all my equipment. No cameras, no cell phones, no food, keep your hands and arms inside the vehicle at all times, &c.

Despite my disappointment, however, it was hard to be sad. I was going to see "Lucy", perhaps the most famous hominin fossil ever discovered, and the B-slab of "Ida", a much older fossil primate that kept me rather busy during the past month. I had seen plenty of casts and replicas of fossil primates, from omomyid skulls in my "Fossil Primates" course to the replicas of extinct hominins at the American Museum of Natural History, but never had I seen authentic primate fossils.

Before being introduced to Lucy, though, visitors to the "Lucy's Legacy" exhibition walk through an assortment of cultural objects from Ethiopia. This section is not tied in very well with the rest of the exhibit, but I do appreciate that the organizers wanted visitors to learn something about the country in which Lucy was found. Much of the floorspace was devoted to the Ethiopian Orthodox Church, which was interesting given the primary subject (i.e. human evolution) of the exhibit.

In the next room visitors are introduced to human evolution through an evolutionary shrub depicting various hominoids and other primates. It is a little hard to follow, particularly since the axis of the chart tracking time changes as you move along (first it is up, then it goes to the right, then it loops around to the left). Still, it is somewhat successful in conveying the diversity of extinct humans and their close relatives (and I was somewhat shocked to see Anoiapithecus, announced just a few weeks ago, in the line-up).

The dimly-lit path then leads visitors to the B-slab of Ida, the 47-million-year old fossil primate from Messel, Germany. This was not the slab featured in all the news reports last month, but a counterslab containing part of Ida's skeleton that was less complete and partially fabricated. Even so, Ida's "lesser half" was still very impressive.

What I had really come to see, though, were Lucy's bones. They were laid out in a waist-high glass case in the center of a room ringed by a new mural by acclaimed paleo-artist Viktor Deak. I did not fall to my knees or have any sort of religious experience. This was not some "holy relic" I had some to pay homage to. Instead Amanda and I looked closely at the bones, quietly discussing Lucy's anatomy.

Replicas of Lucy do not do justice to the real bones. The way the dim lighting glinted off her worn molars, the curvature of her finger bone, the shape of her astragalus ... I had never appreciated these things before. It is a good thing the glass case was there, because I had the urge to pick up the fossils and examine them from other angles. I can't imagine the security guards would have been too happy if I tried.

Deak's mural is also worth some discussion. The art, as always, was impressive, and the symbolism of the painting was both new and familiar. It featured a simplified story of human evolution, from Ardipithecus to Homo sapiens, placing the last 4.5 million years into the space of a 24-hour day (starting at midnight).

The beginnings of the mural are dark and savage. Although the first Ardipithecus reaches out a finger towards the moonlight as if it belonged in Michelangelo's "Creation of Adam", the next two hominins (another Ardipithecus and Australopithecus anamensis) wear ferocious expressions in the dark forest. The impression is that our early history was brutal and savage, but at daybreak the viewer is introduced to the more peaceful-looked Australopithecus afarensis, or Lucy and her kin. (In fact, Lucy is shown holding a child by the water's edge while her mate looks on.)

During the daylight hominins try to avoid predators and practice tool-making, with the genus Paranthropus depicted as a side-branch of the "main-line" of human evolution. By nightfall the surviving hominins (Homo sapiens) can control fire, making their own light, and the present is represented by a well-lit paleoanthropologist's tent. It was technology, developed just after the dawn, that allowed us to tame the night.

It was difficult not to see the mural as a variation on the "March of Progress" theme. Our lineage is shown originating in the dark jungle, developing culture in the light of day, and ultimately having the intelligence and technology to make our own light. It is also interesting that the only mention of branching comes with Paranthropus; all the other hominins are represented as belonging to a straight evolutionary line.

The idea that human evolution followed an Ardipithecus -> Australopithecus anamensis -> Australopithecus afarensis -> Australopithecus garhi -> early Homo path has been fiercely argued by some paleoanthropologists like Tim White (to the point where White argues that we are just giving different names to the same species evolving in the same place). If this is, correct, however, it is a rather startling case of phyletic evolution over more than two million years. I will not dwell on details here, but this is in such start contrast to what we see elsewhere in the vertebrate fossil record that a unilinear trajectory from Ardipithecus to Homo requires extraordinary evidence. (I will have a little more to say about this when I cover White's contribution to the new volume The Paleobiological Revolution).

Such gripes aside, it was truly wonderful to see Lucy's bones. I don't expect that I will have the opportunity to do so ever again. Replicas and photographs can help to educate and popularize certain fossils, but there really is not anything like seeing them for yourself.